A coupler

ABSTRACT

A coupler assembly for coupling implements of the type having two connecting pins, to a vehicle. The coupler has a body component that is connectable to the vehicle, and the body component includes a forward recess for receiving a first connecting pin of an implement. The coupler also has a movable component which is supported by the body component and which is movable through a range of travel relative to the body component. The movable component includes, or forms a part of an aft recess for receiving a second connecting pin of the implement. An actuator selectively moves the movable component relative to the body component. A rear locking member is a part of the movable component and a rear lock actuator allows the rear locking member to be employed to prevent the second connecting pin from exiting the aft recess.

FIELD OF THE INVENTION

This invention relates to a coupler, and in particular, but notexclusively to a coupler for attaching work implements to the arm orboom of an excavator or similar vehicle.

BACKGROUND

Couplers are often used to connect work attachments or implements to thebooms of excavators, diggers, back hoes, etc. The couplers are sometimesalso referred to as “quick hitches”, or “pin grabber” couplers as theygrab the two connecting pins that are attached to many attachments forthe purpose of connecting the attachment to an arm.

The couplers allow implements to be changed quickly and efficiently bybeing able to release the connecting pins of one implement, and to grabthe connecting pins of another, using remotely controlled hydraulicactuators on the coupler.

The ability to quickly change implements however, has lead to anincreasing number of accidents involving implements coming loose, orfalling from diggers etc. Most couplers today will have a safety lockingfeature that will hold one of the pins of an implement if the couplerfails, or if the other pin comes free for some reason.

Experience shows that a single safety lock feature is not sufficient.Accidents are still occurring as a result of the use of these quickchange couplers having a single safety feature. While it is possible toadd additional safety locks, the locks need to be robust to withstandthe harsh environment and rough treatment that couplers experience atthe end of an excavator arm. For example, dirt or other foreign mattercan accumulate within coupler components which may affect the operationof the coupler or its safety features. For this reason any additionalsafety locks need to be relatively simple and durable, to ensure highlevels of reliability of the locks.

There are also limitations concerning the number of hydraulic lines thatare used to control hydraulic couplers. Simply adding additional linesfor each additional safety lock is not always convenient and can becostly to install and maintain. There is a requirement to provideadditional safety features without the need for additional hydrauliclines.

In this specification unless the contrary is expressly stated, where adocument, act or item of knowledge is referred to or discussed, thisreference or discussion is not an admission that the document, act oritem of knowledge or any combination thereof was at the priority date,publicly available, known to the public, part of common generalknowledge; or known to be relevant to an attempt to solve any problemwith which this specification is concerned.

OBJECT

It is therefore an object of the present invention to provide a couplerwhich will at least go some way towards overcoming one or more of theabove mentioned problems, or at least provide the public with a usefulchoice.

STATEMENTS OF THE INVENTION

Accordingly, in a first aspect, the invention may broadly be said toconsist in a coupler assembly for coupling implements having a firstconnecting pin and a second connecting pin, to a vehicle, the couplerhaving;

-   -   a body component that is connectable to the vehicle, and which        includes a forward recess for receiving the first connecting        pin,    -   a movable component which is supported by the body component and        which is movable through a range of travel relative to the body        component, and which includes, or forms a part of, an aft recess        for receiving the second connecting pin, and,    -   a movable component actuator for selectively moving the movable        component relative to the body component,    -   a rear locking member which is a part of the movable component        and which is movable relative to the movable component between        an extended position in which the rear locking member prevents        the second connecting pin from exiting the aft recess and a        retracted position in which the rear locking member does not        prevent the second connecting pin exiting the aft recess,    -   and a rear lock actuator for moving the rear locking member        between its extended and retracted positions.

Preferably a connection between the rear lock actuator and the rearlocking member includes a link member.

Preferably the rear locking member and the link member are configured insuch a manner that;

-   -   an initial range of movement of the link member pushes the rear        locking member from its retracted position to its extended        position, and    -   a second and further range of movement of the link member        positions a stop member which prevents movement of the rear        locking member away from its extended position.

Preferably the stop member is a part of the link member.

Preferably the rear lock actuator is mounted on the movable component.

Preferably the movable component slides relative to the body component.

Preferably the link member slides relative to the movable component.

Preferably the rear locking member is pivotally connected to the movablecomponent.

Preferably the coupler further includes a forward locking member whichis movable relative to the body component between an extended positionin which the forward locking member prevents the first connecting pinfrom exiting the forward recess and a retracted position in which theforward locking member does not prevent the first connecting pin exitingthe forward recess.

Preferably the coupler includes a forward lock actuator for moving theforward locking member between its extended and retracted positions.

Preferably the forward lock actuator is pivotally connected to ahydraulic manifold of the coupler assembly.

Preferably the pivotal connection between the forward lock actuator andthe hydraulic manifold is configured to provide a hydraulic fluid flowpath between the hydraulic manifold and the forward lock actuator.

Preferably the movable component actuator, the rear lock actuator andthe forward lock actuator are all hydraulic actuators.

Preferably a hydraulic system of the coupler includes sequence valves tocontrol the sequence of operation of the movable component actuator, therear lock actuator and the forward lock actuator during any engagementand/or disengagement processes.

In a second aspect, the invention may broadly be said to consist in acoupler assembly for coupling implements having a first connecting pinand a second connecting pin, to a vehicle, the coupler assembly having;

-   -   a forward recess for receiving the first connecting pin,    -   an aft recess for receiving the second connecting pin,    -   a forward locking member for securing the first co/meeting pin        within the forward recess,    -   a hydraulic system including at least one actuator configured to        enable the coupler assembly to positively engage with the first        and second connecting pins of an implement, and    -   the hydraulic system also including at least one hydraulic        manifold block;

wherein the coupler assembly also includes a hydraulic forward lockactuator which is supported on, and receives a hydraulic supply from,the hydraulic manifold block.

Preferably forward lock actuator is pivotally connected to the hydraulicmanifold block.

Preferably the hydraulic supply from the hydraulic manifold block to theforward lock actuator passes through the pivotal connection between theforward lock actuator and the hydraulic manifold block.

Preferably the forward lock actuator is a single acting actuator with aspring return mechanism.

In a third aspect, the invention may broadly be said to consist in avehicle incorporating at least one coupler substantially as specifiedherein.

Preferably the vehicle is an excavator.

In a fourth aspect, the invention may broadly be said to consist in amethod of disengaging a work attachment or implement from a couplerhaving a body and a movable component, including the steps of;

-   -   operating a forward lock actuator to move a forward locking        member from an extended position to a retracted position,    -   operating a rear lock actuator to move a rear locking member        from an extended position to a retracted position,    -   and when the rear locking member is in its retracted position,        operating a movable component actuator to move a movable        component out of engagement with a rear pin of the work        attachment,    -   and then disengaging a forward pin of the work attachment from        the body.

Preferably the method of disengaging includes an automatic operation ofthe forward lock actuator to move the forward locking member from theretracted position to the extended position a pre-determined time periodafter the operation of the forward lock actuator, the rear lock actuatoror the movable component actuator to disengage the coupler from animplement.

The invention may also broadly be said to consist in the parts, elementsand features referred to or indicated in the specification of theapplication, individually or collectively, and any or all combinationsof any two or more of the parts, elements or features, and wherespecific integers are mentioned herein which have known equivalents,such equivalents are incorporated herein as if they were individuallyset forth.

DESCRIPTION

Further aspects of the present invention will become apparent from thefollowing description which is given by way of example only and withreference to the accompanying drawings in which:

FIG. 1 is an exploded perspective view of a first example of a coupleraccording to the present invention,

FIG. 2 is a cutaway perspective view of the first example of a coupler,

FIG. 3 is a cutaway perspective view of a slide assembly of the firstexample of a coupler,

FIG. 4 is a perspective view of a slide component of the slide assembly,

FIG. 5 is a perspective view of a forward locking member of the firstexample of a coupler,

FIG. 6 is a perspective view of a rear locking member of the slideassembly,

FIG. 7 is a perspective view of a link member of the slide assembly,

FIG. 8 is a perspective view of a slide assembly actuator of the firstexample of a coupler,

FIG. 9 is a right side elevation view of the first example of a coupler,

FIG. 10 is a cutaway side elevation view of the first example of acoupler,

FIG. 11 is a perspective view of a rear lock actuator of the firstexample of a coupler,

FIG. 12 is a cutaway side elevation view of the coupler showing a firststage of a coupling sequence,

FIG. 13 is a cutaway side elevation view of the coupler showing a secondstage of a coupling sequence,

FIG. 14 is a cutaway side elevation view of the coupler showing a thirdstage of a coupling sequence,

FIG. 15 is a cutaway side elevation view of the coupler showing a fourthstage of a coupling sequence,

FIG. 16 is a cutaway side elevation view of the coupler showing a firststage of an uncoupling sequence,

FIG. 17 is a cutaway side elevation view of the coupler showing a secondstage of an uncoupling sequence,

FIG. 18 is a cutaway side elevation view of the coupler showing a thirdstage of an uncoupling sequence,

FIG. 19 is a cutaway side elevation view of the coupler showing a fourthstage of an uncoupling sequence,

FIG. 20 is a cutaway side elevation view of the coupler showing a fifthstage of an uncoupling sequence,

FIG. 21 is a schematic diagram of a hydraulic circuit which includescomponents of the coupler as well as hydraulic components of a vehicle,to which the coupler is attached,

FIG. 22 is an electrical diagram used to control the operation of thecoupler,

FIG. 23 is a partially cutaway side elevation view of a second exampleof a coupler according to the present invention, showing a forwardlocking member of the coupler in an extended configuration,

FIG. 24 is a partially cutaway side elevation view of the second exampleof a coupler showing the forward locking member in a retractedconfiguration,

FIG. 25 is a partially cutaway perspective view of the second example ofa coupler which defines an exploded view A, and

FIG. 26 is the exploded view A which shows the hydraulic supply routingto a forward lock actuator which controls the positioning of the forwardlocking member.

FIRST EXAMPLE

With reference to FIGS. 1 to 22, a first example of a coupler assembly(31) is shown in an exploded perspective view and in a series ofperspective and cutaway views. Included also are hydraulic andelectrical circuits used to control the operation of the couplerassembly (31). The coupler assembly (31) is of the type typically usedfor coupling implements having a first connecting pin and a secondconnecting pin, to a vehicle such as an excavator or a back hoe.

It can be seen in FIGS. 1 and 2 that the coupler assembly (31) has abody component (33) that is connectable to the vehicle. The bodycomponent (33) itself includes two coupler mounting pins (35) which areused to connect the coupler assembly (31) to the end of an arm of thevehicle. The body component (33) also includes a forward recess (37) forreceiving the first connecting pin of an implement.

The coupler assembly (31) also includes a movable component or slideassembly (39) which is supported by the body component (33). The slideassembly (39) is movable through a range of travel relative to the bodycomponent (33). The range of travel of the slide assembly (39) issubstantially in a fore and aft direction relative to the body (33). Theslide assembly (39) includes, or at least forms a part of, an aft recess(41) for receiving the second connecting pin of an implement.

A movable component actuator or slide assembly actuator (43) of thecoupler assembly (31) is used to selectively move the slide assembly(39) relative to the body component (33). With reference to FIG. 4 itcan be seen that a slide component (45) of the slide assembly (39)includes elongate tabs (47). These elongate tabs (47) engage withcorresponding slots (49) on the body component (33), allowing the slideassembly (39) to slide in a fore and aft direction relative to the bodycomponent (33).

The slide assembly (39) includes a rear locking member (51). The rearlocking member (51) is movable relative to the slide assembly (39),between an extended position in which the rear locking member (51)prevents the second connecting pin from exiting the aft recess (41) anda retracted position in which the rear locking member (51) does notprevent the second connecting pin exiting the aft recess (41).

The slide assembly (39) also includes a rear lock actuator (53) (referFIGS. 2, 3 and 11) for moving the rear locking member (51) between itsextended and retracted positions. The rear lock actuator (53) is mountedon the slide assembly (39), and moves with the slide assembly (39). Therear lock actuator (53) includes a rear lock actuator spring (54) whichbiases the actuator toward an extended configuration in which the rearlock actuator (53) pushes the rear locking member (51) to its extendedposition.

A feature of the coupler assembly (31) is the connection between therear lock actuator (53) and the rear locking member (51). The connectionincludes a link member (55). The rear locking member (51) is pivotallyconnected to the slide component (45) by a rear lock connecting pin(57). The link member (55) slides fore and aft relative to the slideassembly (39) under the influence of the rear lock actuator (53).

The rear locking member (51) and the link member (55) are configured insuch a manner that an initial range of movement of the link member (55)pushes the rear locking member (51) from its retracted position to itsextended position. And a second and further range of movement of thelink member (55) positions a stop member (59) which prevents movement ofthe rear locking member (51) away from its extended position. In thisexample, the stop member (59) is a part of the link member (55).

It can be seen in FIG. 7 that the link member (55) is in the form of asubstantially rectangular shaped plate (61), having tabs (63) extendingfrom the plate (61) for connection to the rear lock actuator (53). Theplate (61) includes a rectangular shaped hole (65) positionedsubstantially centrally within the principal plane of the plate (61).Alternatively, it could be said that the link member (55) comprises aforward transverse member (67), and aft transverse member (69), and sideplates (71), one on the left side and one on the right side of the linkmember (55). The side plates (71) each span between the outermostextremities of the forward and aft transverse members (67) and (69).

The side plates (71) of the link member (55) engage with, and slidewithin, slide grooves (73) on each side of the slide assembly (39).

Similarly, it can be seen in FIG. 6 that the rear locking member (51)includes an upwardly protruding control tab (75), and two rearwardlyextending locking tabs (77). The two rearwardly extending locking tabs(77) each include a locking surface (79). The locking surfaces (79) aresituated on an upper part of each locking tab (77) and are substantiallyaligned with a lower edge (81) of the slide grooves (73) when the rearlocking member (51) is in its fully extended position.

When the slide assembly (39) is assembled, the link member (55) is heldwithin the slide grooves (73). And when the rear locking member (51) isin its fully extended position, the control tab (75) of the rear lockingmember (51) is situated within the rectangular hole (65) in the linkmember (55). The rectangular hole (65) is of sufficient size to allow arange of movement of the link member (55) relative to the rear lockingmember (51) without contact being made between the link member (55) andthe rear locking member (51). However, movement of the link memberbeyond this range of movement does result in contact between the linkmember (55) and the rear locking member (51). And this contact is usedto move the rear locking member (51) between its retracted position andits extended position as will be explained below.

Movement of the rear locking member (51) from its retracted position toits extended position is achieved as follows. The link member (55) ismoved from its forward most position, and in an aft direction, by therear lock actuator (53). During an initial range of movement of the linkmember (55) in an aft direction, an aft edge (83) of the side plates(71) contacts a forward edge (85) of the locking tabs (77). This contactcauses rotation of the rear locking member (51) about the rear lockconnecting pin (57), and rotation of the rear locking member (51) to itsfully extended position.

Continued movement of the link member (55) in an aft direction does notcause any further movement of the rear locking member (51), however thecontinued movement positions the side plates (71) of the link member(55) over the locking surfaces (79) of the rear locking member (51). Therectangular hole (65) in the link member (55) is configured to allowcontinued aft movement of the link member (55) even though the controltab (75) is now situated within the rectangular hole (65). Also, theslide assembly (39) is configured such that the locking surfaces (79)are immediately adjacent the side plates (71) when the link member (55)is fully aft. In this way, the side plates (71) act as stops preventingmovement of the rear locking member (51) away from its fully extendedposition.

Any forces experienced by the rear locking member (51), for example ifthe second connecting pin of a work implement was trying to exit the aftrecess (41), would result in the locking surfaces (79) bearing upwardsagainst the under side of the side plates (71). This upward force fromthe locking surfaces (79) would be restrained by the engagement of thelink member (55) within the slide grooves (73). This is advantageous inthat these forces experienced by the rear locking member (51) are notfelt directly by the rear lock actuator (53).

Movement of the rear locking member (51) from its extended position toits retracted position is achieved as follows. The link member (55) ismoved forward by the rear lock actuator (53). An initial range offorward movement of the link member (55) moves the side plates (71) awayfrom their location above the locking surfaces (79). This unlocks therear locking member (51) allowing it to be moved to its retractedposition. A second range of forward movement of the link member (55)initially brings a forward edge (87) of the rear transverse member (69)into contact with a rear surface (89) of the control tab (75).

Continued forward movement of the link member (55) pushes the controltab (75) forward causing the rear locking member (51) to move to itsretracted position. The rear locking member (51) is held in itsretracted position by the rear transverse member (69) which lies abovethe control tab (75) and adjacent to it, when the rear locking member(51) is in its retracted position.

The coupler assembly (31) further includes a forward locking member(91). The forward locking member (91) is movable relative to the bodycomponent (33) between an extended position, in which the forwardlocking member (91) prevents the first connecting pin from exiting theforward recess (37), and a retracted position, in which the forwardlocking member does not prevent the first connecting pin exiting theforward recess (37).

The coupler assembly (31) also includes a forward lock actuator (93) formoving the forward locking member (91) between its extended andretracted positions.

In this example, the coupler assembly (31) is used with a hydrauliccontrol system (111) and an electrical control circuit (113) as shown inFIGS. 21 and 22 respectively.

The electrical control circuit (113) includes two manually controlledswitches and a timer, and the hydraulic control system (111) includessolenoid operated control valves and sequence valves, to control thesequence of operation of the slide assembly actuator (43), the rear lockactuator (53) and the forward lock actuator (93), during any engagementand/or disengagement processes. The design of the hydraulic controlsystem (111) allows the coupler assembly (31) to be controlled usingonly two hydraulic lines. The electrical and hydraulic control systemswill now be explained in further detail.

The electrical control circuit (113) has a master switch (115) which isused to supply or disconnect electrical power to the control circuit.When the master switch (115) is switched on an alarm (117) sounds andoptionally a warning light operates also. This warns personal in thevicinity of the vehicle that the coupler (31) will be operated torelease and/or engage implements from the aim of the vehicle.

A second switch (119) is a ‘hold to run’ style of switch, meaning thatthe contacts of the switch are only engaged while the operator continuesto hold the switch down. When the second switch (119) is pushed “on” asecond alarm (121) and warning light operates, and power is supplied toa first solenoid operated valve (123) of the hydraulic control system(111). A timer (125) is also initiated, which in turn provides power toa second solenoid operated valve (127) via a timer relay (128), after apre-determined time period, for example a time period in the range ofthree to eight seconds.

The first and second solenoid operated valves (123) and (127) of thehydraulic control system (111) are situated on the vehicle along with apressure regulating valve (129) for regulating the hydraulic pressure toa set value and minimising pressure spikes. The first solenoid operatedvalve (123) is used to initiate the disengage or engage signals to thecoupler (31). The second solenoid operated valve (127) controls thedraining of hydraulic fluid from the forward lock actuator (93) afterthe pre-determined time delay period to allow a forward lock actuatorspring (99) within the forward lock actuator (93) to move the forwardlocking member (91) backs to its extended position.

Two hydraulic lines, a supply line (131) and a return line (133), areused to power and control the coupler assembly (31).

The coupler assembly (31) itself includes a first sequence valve (135)which controls the sequencing of the three actuators and ensures thatthe rear lock actuator (53) and the forward lock actuator (93) operateto retract their respective locking members (51) and (91) prior to theretraction of the slide assembly actuator (43) to move the slideassembly (39) forward.

A first pressure operated check valve (137) and a second pressureoperated check valve (139) act as safety locks to lock the position ofthe slide assembly actuator (43) in case of a hydraulic failure. Thelocked slide assembly actuator (43) holds the slide assembly (39) fixedpreventing the pins of an implement from exiting the forward and aftrecess (37) and (41) of the coupler (31).

A second sequence valve (141) controls the sequencing of the slideassembly actuator (43) and the rear lock actuator (53) to ensure thatthe rear lock actuator (43) moves the rear locking member (51) to itsretracted position before the slide assembly actuator (43) begins tomove the slide assembly (39) aft.

A third pressure operated check valve (143) isolates the rear lockactuator (53) from the forward lock actuator (93) when fluid is drainedfrom the forward lock actuator (93) by the second solenoid operatedvalve (127) as described above.

With reference to FIGS. 15 to 20 the dis-engagement sequence will now bedescribed.

At the beginning of this sequence (refer FIG. 15) the slide assemblyactuator (43) is at least partly extended and is holding the slideassembly (39) in engagement with an aft connecting pin (95) of animplement. The rear lock actuator (53) is extended under hydraulicpressure and the rear locking member (51) is in its extended positionand is able to prevent the aft connecting pin (95) from exiting the aftrecess (41). The forward lock actuator is retracted under spring tensiononly and is holding the forward locking member (91) in its extendedposition and is able to prevent a forward connecting pin (97) fromexiting the forward recess (37).

To initiate the disengagement procedure, the master switch (115) isswitched on. Then the second switch (119), the ‘hold to run switch’ isdepressed. The first solenoid operated valve (123) then operates toprovide hydraulic pressure to the return line (133). Due to theconfiguration of the first sequence valve (135) the hydraulic pressureis initially directed to the rear lock actuator (53) and the forwardlock actuator (93) to retract the rear and forward locking members (51)and (91)—refer to FIG. 16.

When the rear lock actuator (53) and the forward lock actuator (93) haveoperated, pressure in the return line (133) builds until the firstsequence valve (135) opens to allow pressure to the retract side of theslide assembly actuator (43) and to the pilot line of the first pressureoperated check valve (137), allowing the slide assembly actuator (43) toretract and to move the slide assembly (39) fully forward—refer to FIG.17. This disengages the aft connecting pin (95) from the aft recess(41).

Then the coupler assembly (31) is rotated, for example by using thecrowd actuator of the excavator, to allow the coupler assembly (31) tobe moved aft without re-engaging with the aft connecting pin (95) in theaft recess (41)—refer FIG. 18.

Then the coupler assembly (31) is moved aft to disengages the forwardconnecting pin (97) from the forward recess (37) to complete thedisengaging procedure—refer FIG. 19.

FIG. 20 shows the subsequent movement of the forward locking member (91)to its extended position after the time delay period. After the set timeperiod, the second solenoid operated valve (127) operates to vent thefluid from the forward lock actuator (93), allowing a spring (9) withinthe forward lock actuator (93) to retract the actuator and move theforward locking member (91) to its extended position. The pressureoperated check valves (137), (139) and (143) prevent any movement offluid from the slide assembly actuator (43) and the rear lock actuator(53). This automatic resetting of the forward locking member (91) to itsextended position is a safety feature ensuring that the forward lockingmember (91) is ready to hold and secure the forward connecting pin (97)of the next implement in the forward recess (37) as soon as the pick upor engagement procedure begins.

With reference to FIGS. 12 to 15 the engagement sequence will now bedescribed.

The rear locking member (51) is retracted, and as noted above, theforward locking member (91) is extended and ready to hold and secure theforward connecting pin (97).

The coupler assembly (31) is manipulated, for example using the arm ofthe excavator, to engage the forward connecting pin (97) of the nextimplement within the forward recess (37). The forward locking member(91) is configured so that it is pushed away from its extended positionby the forward connecting pin (97) as it enters the forward recess(37)—refer to FIG. 12. The coupler assembly (31) is configured such thatthe spring (99) pushes the forward locking member (91) back to itsextended position once the forward connecting pin (97) has passed fullyinto the forward recess (37)—refer to FIG. 13.

The operator of the excavator then rotates the coupler assembly (31)until the body (33) touches the aft connecting pin (95) of theimplement. And then the ‘hold to run’ or second switch (119) is releasedby the operator. This causes the first solenoid operated valve (123) tobecome de-energised and it returns to its steady state configuration asshown in FIG. 21. This connects the hydraulic supply pressure to thesupply line (131). This supplies hydraulic pressure to the extend sideof the slide assembly actuator (43) and opens the second pressureoperated check valve (139) allowing the slide assembly actuator (43) toextend and to move the slide assembly (39) aft toward the aft connectingpin (95)—refer to FIG. 14.

When the slide assembly (39) engages with the aft connecting pin (95)the pressure builds on the extend side of the slide assembly actuator(43) until there is sufficient pressure to operate the second sequencevalve (141). Then pressure is supplied to the extend side of the rearlock actuator (53), the rear lock actuator (53) then extends and movesthe rear locking member to its extended position—refer to FIG. 15.

This is the configuration that the coupler assembly (31) remains inwhile the excavator or other vehicle is using the coupler assembly (31)to hold an implement. A first locking feature is provided by the firstand second pressure operated check valves (137) and (139) whichhydraulically lock the slide assembly actuator (43) in the case of ahydraulic failure, for example a rupture of the supply or return lines(131) or (133). A second locking feature is provided by the forwardlocking member (91) which holds the forward connecting pin (97) withinthe forward recess (37). And a third locking feature is provided by therear locking member (51) which holds the aft connecting pin (95) withinthe aft recess (41).

It can be said that in use, the coupler assembly (31) employs thefollowing method of disengaging a work attachment or implement from thecoupler assembly (31);

-   -   the forward lock actuator (93) is operated to move the forward        locking member (91) from its extended position to its retracted        position,    -   the rear lock actuator (53) is operated to move the rear locking        member (51) from its extended position to its retracted        position,    -   and when the rear locking member (51) is in its retracted        position, the slide assembly actuator (43) is operated to move        the slide assembly (39) out of engagement with a rear pin (95)        of the work attachment,    -   and when the forward locking member (91) is retracted and the        rear pin (95) is no longer engaged within the slide assembly        (39), the forward pin (97) of the work attachment is disengaged        from the body (33).

With the coupler assembly (31), the method of disengaging also includesan automatic operation of the forward lock actuator (93) to move theforward locking member (91) from the retracted position to the extendedposition a pre-determined time period after the operation of;

-   -   the forward lock actuator (93),    -   the rear lock actuator (53), or    -   the slide assembly actuator (43),

to disengage the coupler (31) from an implement.

SECOND EXAMPLE

With reference to FIGS. 23 to 26, a second example of a coupler assembly(161) will now be described. The operation of the coupler assembly (161)is similar to that of the first example of a coupler assembly (31), andthe only significant difference between the first and second examples isthe configuration of a forward locking assembly (163).

In this second example, a forward lock actuator (165) of the forwardlocking assembly (163) is pivotally connected at its aft end to ahydraulic manifold block (167) of the coupler assembly (164 In this waythe forward lock actuator (165) is supported by the hydraulic manifoldblock (167). The hydraulic manifold block (167) routes fluid for a slideactuator (169) and a rear lock actuator (171), and also routes hydraulicfluid directly to the forward lock actuator (165).

A pivot pin (173) connects an aft end of the forward lock actuator (165)to the hydraulic manifold block (167). A first passage (175) within thehydraulic manifold block (167) communicates with a second passage (177)within the pivot pin (173). The second passage (177) communicates withthe hydraulic cylinder (179) of the forward lock actuator (165) via athird passageway (181) in an end fitting (183) of the forward lockactuator (165).

In this way, hydraulic fluid can be directed to or from the forward lockactuator (165) to extend or retract a forward locking member (185). Ascan be seen in FIG. 26, the forward lock actuator (165) is a singleacting actuator with a spring return mechanism. For this reason theforward lock actuator (165) only requires a single hydraulic supply.

This configuration eliminates the need for an external hydraulicconnection to the forward lock actuator (165), while at the same timeallowing the forward lock actuator (165) to pivot as it moves theforward locking member (185). This allows a compact configuration of theforward locking assembly (163), and the configuration is expected tohave a high reliability.

Variations

To those skilled in the art to which the invention relates, many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the scope ofthe invention as defined in the appended claims. The disclosures and thedescription herein are purely illustrative and are not intended to be inany sense limiting.

In the examples described above, the slide assembly actuator, the rearlock actuator and the forward lock actuator are all hydraulic actuators.However it is envisaged that alternative actuators could be used, forexample electrically operated linear actuators.

Definitions

Throughout this specification the word “comprise” and variations of thatword, such as “comprises” and “comprising”, are not intended to excludeother additives, components, integers or steps.

Advantages

Thus it can be seen that at least the preferred form of the inventionprovides a coupler which provides a high level of safety. The rearlocking member locks the aft connecting pin positively within the aftrecess and the arrangement of the rear lock actuator and its connectionto the rear locking member provides a positive and robust lock of therear locking member in its extended position. The configuration of thelocks is relatively simple and not excessively prone to interferencefrom dirt or other foreign matter that may accumulate around thecomponents.

The coupler assembly can be controlled using only two hydraulic lineswhich is advantageous as it eliminates the need for additional lineswhere two are already available.

Also, the hydraulic actuators for the slide assembly, for the forwardlock and the rear lock are all isolated from one another, meaning thatin the event of a failure of one of the actuators, the other two willcontinue to provide their safety locking features. In addition, eachactuator includes a biasing means in the form of a spring which biaseseach actuator toward a fail-safe configuration, that is, a configurationwhich retains the pins of the implements within the coupler.

1. A coupler assembly for coupling implements having a first connectingpin and a second connecting pin, to a vehicle, the coupler having; abody component that is connectable to the vehicle, and which includes aforward recess for receiving the first connecting pin, a movablecomponent which is supported by the body component and which is movablethrough a range of travel relative to the body component, and whichincludes, or forms a part of, an aft recess for receiving the secondconnecting pin, and, a movable component actuator for selectively movingthe movable component relative to the body component, a rear lockingmember which is a part of the movable component and which is movablerelative to the movable component between an extended position in whichthe rear locking member prevents the second connecting pin from exitingthe aft recess and a retracted position in which the rear locking memberdoes not prevent the second connecting pin exiting the aft recess, and arear lock actuator for moving the rear locking member between itsextended and retracted positions.
 2. The coupler assembly as claimed inclaim 1, wherein a connection between the rear lock actuator and therear locking member includes a link member.
 3. The coupler assembly asclaimed in claim 2, wherein the rear locking member and the link memberare configured in such a manner that; an initial range of movement ofthe link member pushes the rear locking member from its retractedposition to its extended position, and a second and further range ofmovement of the link member positions a stop member which preventsmovement of the rear locking member away from its extended position. 4.The coupler assembly as claimed in claim 2, wherein the stop member is apart of the link member.
 5. The coupler assembly as claimed in claim 1,wherein the rear lock actuator is mounted on the movable component. 6.The coupler assembly as claimed in claim 1, wherein the movablecomponent slides relative to the body component.
 7. The coupler assemblyas claimed in claim 2, wherein the link member slides relative to themovable component.
 8. The coupler assembly as claimed in claim 1,wherein the rear locking member is pivotally connected to the movablecomponent.
 9. The coupler assembly as claimed in claim 1, wherein thecoupler further includes a forward locking member which is movablerelative to the body component between an extended position in which theforward locking member prevents the first connecting pin from exitingthe forward recess and a retracted position in which the forward lockingmember does not prevent the first connecting pin exiting the forwardrecess.
 10. The coupler assembly as claimed in claim 9, wherein thecoupler includes a forward lock actuator for moving the forward lockingmember between its extended and retracted positions.
 11. The couplerassembly as claimed in claim 10, wherein the forward lock actuator ispivotally connected to a hydraulic manifold of the coupler assembly. 12.The coupler assembly as claimed in claim 11, wherein the pivotalconnection between the forward lock actuator and the hydraulic manifoldis configured to provide a hydraulic fluid flow path between thehydraulic manifold and the forward lock actuator.
 13. The couplerassembly as claimed in claim 1, wherein a hydraulic system of thecoupler includes sequence valves to control the sequence of operation ofthe movable component actuator, the rear lock actuator and the forwardlock actuator during any engagement and/or disengagement processes. 14.A coupler assembly for coupling implements having a first connecting pinand a second connecting pin, to a vehicle, the coupler assembly having;a forward recess for receiving the first connecting pin, an aft recessfor receiving the second connecting pin, a forward locking member forsecuring the first connecting pin within the forward recess, a hydraulicsystem including at least one actuator configured to enable the couplerassembly to positively engage with the first and second connecting pinsof an implement, and the hydraulic system also including at least onehydraulic manifold block; wherein the coupler assembly also includes ahydraulic forward lock actuator which is supported on, and receives ahydraulic supply from, the hydraulic manifold block.
 15. The couplerassembly as claimed in claim 14, wherein forward lock actuator ispivotally connected to the hydraulic manifold block.
 16. The couplerassembly as claimed in claim 15, wherein the hydraulic supply from thehydraulic manifold block to the forward lock actuator passes through thepivotal connection between the forward lock actuator and the hydraulicmanifold block.
 17. The coupler assembly as claimed in claim 14, whereinthe forward lock actuator is a single acting actuator with a springreturn mechanism.
 18. A vehicle incorporating at least one couplersubstantially as claimed in claim
 1. 19. A method of disengaging a workattachment or implement from a coupler having a body and a movablecomponent, including the steps of; operating a forward lock actuator tomove a forward locking member from an extended position to a retractedposition, operating a rear lock actuator to move a rear locking memberfrom an extended position to a retracted position, and when the rearlocking member is in its retracted position, operating a movablecomponent actuator to move a movable component out of engagement with arear pin of the work attachment, and then disengaging a forward pin ofthe work attachment from the body.
 20. The coupler assembly as claimedin claim 19, wherein the method of disengaging includes an automaticoperation of the forward lock actuator to move the forward lockingmember from the retracted position to the extended position apre-determined time period after the operation of the forward lockactuator, the rear lock actuator or the movable component actuator todisengage the coupler from an implement.